Verna Alessio, Marasso Simone Luigi, Rivolo Paola, Parmeggiani Matteo, Laurenti Marco, Cocuzza Matteo
Chilab-Materials and Microsystems Laboratory, DISAT, Politecnico di Torino-Via Lungo Piazza d'Armi 6, IT 10034 Chivasso (Torino), Italy.
CNR-IMEM, Parco Area delle Scienze 37a, IT 43124 Parma, Italy.
Micromachines (Basel). 2019 Jun 25;10(6):426. doi: 10.3390/mi10060426.
Graphene and 2D materials have been exploited in a growing number of applications and the quality of the deposited layer has been found to be a critical issue for the functionality of the developed devices. Particularly, Chemical Vapor Deposition (CVD) of high quality graphene should be preserved without defects also in the subsequent processes of transferring and patterning. In this work, a lift-off assisted patterning process of Few Layer Graphene (FLG) has been developed to obtain a significant simplification of the whole transferring method and a conformal growth on micrometre size features. The process is based on the lift-off of the catalyst seed layer prior to the FLG deposition. Starting from a SiO finished Silicon substrate, a photolithographic step has been carried out to define the micro patterns, then an evaporation of Pt thin film on AlO adhesion layer has been performed. Subsequently, the Pt/AlO lift-off step has been attained using a dimethyl sulfoxide (DMSO) bath. The FLG was grown directly on the patterned Pt seed layer by Chemical Vapor Deposition (CVD). Raman spectroscopy was applied on the patterned area in order to investigate the quality of the obtained graphene. Following the novel lift-off assisted patterning technique a minimization of the de-wetting phenomenon for temperatures up to 1000 °C was achieved and micropatterns, down to 10 µm, were easily covered with a high quality FLG.
石墨烯和二维材料已被应用于越来越多的领域，人们发现沉积层的质量是所开发器件功能的关键问题。特别是，高质量石墨烯的化学气相沉积（CVD）在后续的转移和图案化过程中也应保持无缺陷。在这项工作中，已开发出一种剥离辅助图案化工艺来制备少层石墨烯（FLG），以显著简化整个转移方法，并在微米尺寸的特征上实现保形生长。该工艺基于在FLG沉积之前剥离催化剂种子层。从完成SiO处理的硅衬底开始，进行光刻步骤以定义微图案，然后在AlO粘附层上蒸发Pt薄膜。随后，使用二甲基亚砜（DMSO）浴实现Pt/AlO剥离步骤。通过化学气相沉积（CVD）在图案化的Pt种子层上直接生长FLG。对图案化区域应用拉曼光谱来研究所得石墨烯的质量。采用新型剥离辅助图案化技术后，在高达1000°C的温度下实现了去湿现象的最小化，并且低至10 µm的微图案很容易被高质量的FLG覆盖。
